Reciprocity - an indirect evolutionary analysis

This paper investigates strategic interaction between rational agents whose preferences evolve over time. Players face a pecuniary �game of life� comprising the ultimatum game and the dictator game. Utility may but need not be attached to the reciprocation of fair and unfair play by the opponent and equitable payoff distributions as proposed by Falk and Fischbacher (2001). Evolutionary fitness is determined solely by material success � regardless of the motives for its achievement. Agents cannot explicitly condition the social component of their preferences on whether they face the ultimatum or dictator game. Under these conditions, agents develop a strong preference for reciprocation but little interest in an equitable distribution as such. This corresponds to equitable ultimatum offers but full surplus appropriation by dictators. Adding an exogenous constraint on the possible divergence between preference for reciprocation and for an equitable distribution either makes ultimatum divisions asymmetric or dictators become generous depending on the relative frequency of ultimatum and dictator interaction.

Selfishness, fraternity, and other-regarding preference in spatial evolutionary games

Spatial evolutionary games are studied with myopic players whose payoff interest, as a personal character, is tuned from selfishness to other-regarding preference via fraternity. The players are located on a square lattice and collect income from symmetric two-person two-strategy (called cooperation and defection) games with their nearest neighbors. During the elementary steps of evolution a randomly chosen player modifies her strategy in order to maximize stochastically her utility function composed from her own and the co-players' income with weight factors $1-Q$ and Q. These models are studied within a wide range of payoff parameters using Monte Carlo simulations for noisy strategy updates and by spatial stability analysis in the low noise limit. For fraternal players ($Q=1/2$) the system evolves into ordered arrangements of strategies in the low noise limit in a way providing optimum payoff for the whole society. Dominance of defectors, representing the "tragedy of the commons", is found within the regions of prisoner's dilemma and stag hunt game for selfish players (Q=0). Due to the symmetry in the effective utility function the system exhibits similar behavior even for Q=1 that can be interpreted as the "lovers' dilemma".Comment: 7 two-column pages, 8 figures; accepted for publication in J. Theor. Bio

Are moral objections to free riding evolutionarily stable?

Game Theory;Public Goods

Why and How Identity Should Influence Utility

This paper provides an argument for the advantage of a preference for identity-consistent behaviour from an evolutionary point of view. Within a stylised model of social interaction, we show that the development of cooperative social norms is greatly facilitated if the agents of the society possess a preference for identity consistent behaviour. As cooperative norms have a positive impact on aggregate outcomes, we conclude that such preferences are evolutionarily advantageous. Furthermore, we discuss how such a preference can be integrated in the modelling of utility in order to account for the distinctive cooperative trait in human behaviour and show how this squares with the evidence

Equilibrium Vengeance

This paper introduces two ideas, emotional state dependent utility components (ESDUCs), and evolutionary perfect Bayesian equilibrium (EPBE). Using a simple extensive form game, we illustrate the efficiency-enhancing role of a powerful ESDUC, the vengeance motive. Incorporating behavioral noise and observational noise leads to a range of (short run) Perfect Bayesian equilibria (PBE) involving both vengeful and non-vengeful types. We then derive two (long run) EPBE, one where both types survive and reap mutual gains, and a second where only the non-vengeful type survives and there are no mutual gains.negative reciprocity, perfect Bayesian equilibrium, evolutionary perfect Bayesian equilibrium, emotional state dependent utility

Sequential vs. Simultaneous Schelling Models: Experimental Evidence

This paper shows the results of experiments where subjects play the Schelling's spatial proximity model (1969, 1971a). Two types of experiments are conducted; one in which choices are made sequentially, and a variation of the first where the decision-making is simultaneous. The results of the sequential experiments are identical to Schelling's prediction: subjects finish in a segregated equilibrium. Likewise, in the variant of the simultaneous decision experiment the same result is reached: segregation. Subjects’ heterogeneity generates a series of focal points in the first round. In order to locate themselves, subjects use these focal points immediately, and as a result, the segregation takes place again. Furthermore, simultaneous experiments with commuting costs allow us to conclude that introducing positive moving costs does not affect segregation.Schelling models, economic experiments, segregation

A model of labour supply with job offer restrictions

Labour Supply;Models

Herd behavior, the "Penguin effect", and the suppression of informational diffusion: An analysis of informational externalities and payoff interdependency

Technology;Information;Econometric Models;Group Behaviour

Who is Post-Walrasian Man?

This paper, written for a conference volume on "post-Walrasian macro-economics," reviews what we have learned, and perhaps not learned, about the character of economic man over the last few decades, and discusses some of the macroeconomic implications of this research.

When envy helps explain coordination

This paper identifies a class of symmetric coordination games in which the presence of envious people helps players to coordinate on a particular strict Nash equilibrium. In these games, the selected equilibrium is always risk-dominant. We also find that envious preferences are evolutionary stable when they lead to Pareto-efficiency.Envy Coordination games Risk-dominance Evolutionary stability